Prediction Markets

Topic Owners: Matthew, Elisabeth

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Precis

Our seminar this week aims to discuss novel and/or controversial applications of prediction markets. Our study will be organized into three parts. First, before class everyone will get acquainted with prediction markets as they now exist and understand the basic economic theory behind their success--this page and the first required reading (the Wolfers/Zitzewitz article) will cover that background. We also tried a (failed!) experiment with creating our own prediction markets on intrade.net that inadvertently taught a lesson about how difficult it is to get efficient information markets (more below). Second, we will examine a few proposals for how prediction markets might be used at the frontier. The readings cover Professor Wolfers' crime prediction market, the DARPA project, and the Google Flu Tracker. In class, Professor Wolfers' will expand on the crime prediction market, and Bo Cowgill of Google will add some insight into Google's internal prediction markets. Third and finally, we will try to generalize from these examples some basic principles about what prediction markets can and cannot do well. At this point, we will consider skeptical arguments, both the set of (weak but popular) moral objections and more sophisticated practical/theoretical worries. Ultimately, the class will come to some conclusions about what types of uses prediction markets might have, perhaps inventing some ideas of our own.

I. What Prediction Markets Do Now

The most high-profile examples of prediction marketsthe Iowa Electronic Markets and Intradestarted by focusing primarily on predicting election outcomes and related political and financial events. Now they have expanded to cultural (Oscars) and technological (X Prize) events as well. The status of the commercial prediction markets is uncertain; for example, Tradesports announced recently that it is closing. And questions remain about the legal status of prediction markets, whether the CTFC will regulate them, and whether they will be taxed.

Rather than focusing on the traditional markets, however, we want to focus on future applications of prediction markets, particularly their possible use by government or by government-industry collaboration. We'd like to explore in particular applications that are likely to be controversial.

The focus will be three cases that we think raise interesting legal and ethical questions.

• Crime rate predictions, a la this proposal

• Google's flu-tracking application (where, as Professor Zittrain noted, the predictors aren't even aware that their knowledge is being harvested)

• the failed DARPA terrorist futures market

Guests

Justin Wolfers, Economist (confirmed)

Hal Varian, Google (possibly, on videoconference)

Concrete Questions

• Which of these applications are most likely and desirable?

• Should the government be involved in administering prediction markets at all? Should it regulate them?

• What ethical concerns do we have about prediction markets of the future, and how might we address them? Can design of the markets help mitigate concerns? Are some more fundamental?

Tech Tweak/Experiment

Everyone will create their own prediction market contract via intrade.net. Once you set up an account there, you can then create you own contract at http://www.intrade.net/market/create/start.faces. Your contract can be about anything you like (doesn't have to be legal), but it should conclude before our class date, April 27, 2009. The idea is (1) for everyone to get a feel for how prediction markets operate; (2) to see what kinds of contracts get enough volume to be successful and what kinds don't; (3) to see how accurate the predictions are, how they change over time, etc.

Once you've signed up and created a contract -- please do so by Friday, March 20 -- you can invite other people in the class to bet on your contract to give it some initial starting volume. (Intrade.net gives everyone $10k in play money upon signing up, so obviously if people want to bet on the wider world's contracts, that's great too). Everyone should list the contracts they've created below to facilitate class participation on intrade (and so that we can generate a variety of different kinds of contracts). At the actual class session on April 27, everyone should come in prepared to briefly discuss what happened with their contract (feel free to create more than one).

Readings

• Prediction Markets

Justin Wolfers and Eric Zitzewitz | 18 Journal of Economic Perspectives 107 (2004) | (19 pages, essential background--only one equation for the math-phobic)

• Google Uses Searches to Track Flu’s Spread

Miguel Helft | New York Times | November 11, 2008 | (1 page, useful diagram)

• Predicting Crime

M. Todd Henderson, Justin Wolfers, and Eric Zitzewitz | Olin Working Paper No. 402 | April 2008 | (5 pages, just read abstract and introduction)

• Collection of Newspaper Articles on the DARPA Markets

Carl Hulse of the NYT and Wire Services | July 2003 | (~6 pages)

• Dorgan Speech Daschle Speech

Discussion of the DARPA Markets in the Senate | July 28 and 29, 2003 | (2 short comments, mostly for humor value)

• Prediction Markets and Law: A Skeptical Account

Student Note | 122 Harvard Law Review 1217 (2009) | (21 pages, actually good critical arguments)

Optional Readings

• • A brief paper describing the failed DARPA terrorism futures market, by a Professor at the Naval Postgraduate School. Robert Looney, DARPA’s Policy Analysis Market for Intelligence: Outside the Box or Off the Wall?, STRATEGIC INSIGHTS (2003).

• Professor Sunstein's Infotopia

• Robin Hanson's Futarchy proposal

• Cass R. Sunstein, Group Judgments: Statistical Means, Deliberation, and Information Markets, 80 N.Y.U. L. Rev. 962 (2005)

• Paper on the application of prediction markets to corporate governance

• Chapter 10 of Michael Abramowicz's book Predictocracy

Class-Constructed Markets

• Matthew: 2009 Virginia Attorney General Race

• Elisabeth: US To Lift Sanctions Against Cuba by end of 2009

• CKennedy: A Million Chinese Charterists

• Dulles: Congress or FCC strengthens network neutrality principles by the end of 2010.

• Dan: U.S. Supreme Court strikes down all or part of § 5 of the VRA this Term

Andrew: Will General Motors file for Chapter 11 by April 20, 2009? http://www.intrade.net/market/detail/?contractId=338028#GM_Files_for_Chapter_11_by_4/20/09%3F

• Debbie: Nesson Takes Down the RIAA

• Msanchez: U.S. Recording Industry Cease Filing File-sharing Lawsuits

• Lee: In vitro meat for sale in US before 2020

• Ayelet: U2 performs in Boston by the end of 2009

• Shubham: New HLS Dean to be named by June 15, 2009

• JG: A major world airline switches the default pilot for its flights over to computer (i.e. perhaps human copilot, but no human pilot) by 2020

• Rainer: IPv6 traffic makes up at least 1 percent of all internet traffic by the end of 2010.

• Cooper: Red Sox win 2009 World Series

• Dharmishta: Android phone sales surpass iPhone sales by 2012

• Gwen: I'm having trouble getting an account set up. Do you have to mail in a check? I get this error message when I try to use credit cards: "Unfortunately your bank has refused to authorise your deposit. Most US-based members are no longer able to fund their accounts by credit card due to the passage of recent legislation through the US Congress. Many non-US banks have also adopted a similar policy and will no longer authorise credit card transactions with certain classes of merchants. For more information about your attempted deposit please contact your bank. If you require assistance with funding your account by another method please e-mail us at help@intrade.com . We are happy to accept deposits by check, money order or bank transfer. Please see your My Account screen for more details." What law is this, and how recently did it change? [Elisabeth: Intrade.net is a free site -- you shouldn't have to use your credit card! You might be at the wrong site?]